For those that have brought the new ipad Pro 10.5 and are experiencing digital noise and latency issue on the 3.5mm headphone output after a few minutes there are threads about this on the audiobus forum here:

The temporary solution that people have found that works until a proper fix is provided is here:

The SOLUTION for me is just this:

Clean the internal RAM (shut of/home button for five seconds)
Start Beatmaker 3/ Auria / Cubasis etc with the audiocable plugged in (headphone/speaker system)
Wait 10 seconds
Unplug the cable for at least five seconds
Replug the cable
Have fun for several hours without any problem!